JP2017038110A - Image sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent foreign matter from entering a light receiving body without irradiating the light receiving body with light other than light condensed by a lens body. A light guide that extends in a main scanning direction and emits light to an object to be read; a lens body that converges reflected light reflected by the object to be read; and the reflection that is converged by the lens body. A light receiving body that receives light, and a housing that stores or holds the light guiding body, the lens body, and the light receiving body and is formed by bending a sheet metal, and the housing is in a main scanning direction. And a bottom portion formed with a slit portion through which the reflected light that has passed through the lens body is formed, and a main scan that is bent inward at a predetermined angle from both ends of the slit portion in the sub-scanning direction. A pair of lens body fixing portions extending in the direction is provided, and the side surface of the lens body inserted between the pair of lens body fixing portions and the lens body fixing portion are fixed by a light shielding body. [Selection] Figure 5

Description

  The present invention relates to an image sensor that is used in an image reading apparatus such as a copier or a digital multifunction peripheral and reads an image of a document.

  The optical system of the image sensor irradiates uniform light in the main scanning direction (longitudinal direction) with the demand for uniformity of reading depth and higher resolution of copying machines, etc. A structure that defines the position with high accuracy is required. International Publication No. 2013/168537 (see Patent Document 1) includes a lens body holding portion 212 formed of a resin, and the lens body 15 is inserted into an opening of the lens body holding portion 212 so that the lens body 15 A structure for adjusting the position is disclosed.

International Publication No. 2013/168537

  However, the one described in Patent Document 1 has a problem that there is no detailed disclosure regarding light shielding in the gap between the lens body 15 and the lens body holding portion 212.

  The present invention has been made to solve the above-described problems, and does not irradiate the photoreceptor with light other than the light collected by the lens body, and more reliably prevents foreign matter from entering the photoreceptor. An image sensor is obtained.

  An image sensor according to the present invention extends in the main scanning direction, emits light to a reading object, a lens body that converges reflected light reflected by the reading object, and converges by the lens body A light receiving body that receives the reflected light, and a housing that stores or holds the light guide body, the lens body, and the light receiving body and that is formed by bending a sheet metal, A bottom portion formed with a slit portion extending in the main scanning direction and through which the reflected light that has passed through the lens body is formed, and inwardly inclined at a predetermined angle from both ends of the slit portion in the sub-scanning direction. A pair of lens body fixing portions that are bent and extend in the main scanning direction, and a side surface of the lens body that is inserted between the pair of lens body fixing portions and the lens body fixing portion are fixed by a light shielding body It is.

  According to the present invention, an image that more reliably prevents foreign matter from entering the light receiving body by providing the light shielding body on the side surface of the lens body that collects the reflected light from the object to be read from the document or the like on the light receiving body. There is an effect of obtaining a sensor.

1 is a developed perspective view of an overall configuration of an image sensor according to Embodiment 1 of the present invention. 1 is a configuration perspective view showing in detail a part of an image sensor according to Embodiment 1 of the present invention. 1 is a configuration perspective view showing in detail a part of an image sensor according to Embodiment 1 of the present invention. It is sectional drawing of the main scanning direction of the lens unit in the image sensor which concerns on Embodiment 1 of this invention. It is sectional drawing of the subscanning direction of the lens unit in the image sensor which concerns on Embodiment 1 of this invention. It is sectional drawing of the subscanning direction of the housing | casing in the image sensor which concerns on Embodiment 1 of this invention.

Embodiment 1 FIG.
FIG. 1 is an exploded perspective view of the overall configuration of an image sensor 100 according to Embodiment 1 of the present invention. 2 and 3 are perspective views showing in detail a part of the image sensor 100 according to Embodiment 1 of the present invention. FIG. 2 is a view seen from the same direction as FIG. 1, and FIG. FIG. 2 is a view of FIG. 2 viewed from the side opposite to FIG.

  In FIG. 1, a document M is a reading object of the image sensor 100, and the document M is in contact with the transparent plate 1 with the reading surface facing the transparent plate 1. Although not shown, the document M is transported to the image sensor 100 by a transport mechanism, and the image sensor 100 reads an image of the document M in contact with the transparent plate 1. In describing the embodiment of the present invention, the main scanning direction, the sub-scanning direction, and the height direction are defined as follows. The main scanning direction is the longitudinal direction of the image sensor 100. The sub-scanning direction is the short direction of the image sensor. Further, the height direction is a normal direction of the reading surface of the original M, that is, a direction orthogonal to both the main scanning direction and the sub-scanning direction.

  This will be described in more detail with reference to FIGS. The image sensor 100 irradiates light on the reading surface of the document M, collects the reflected light reflected by the reading surface, and is assembled inside the lens unit 2. A light unit 3 that enters from both ends in the main scanning direction and irradiates the original M with light, and a sensor unit 4 that converges and receives the light collected by the lens unit 2 are provided.

  The lens unit 2 extends in the main scanning direction and collects the reflected light reflected by the reading surface of the document M, and the light unit 3, the sensor unit 4, and the housing 6 that fixes the lens body 5. , A light shielding body 7 for adhering light incident on the sensor unit 4 side between the side surface of the lens body 5 in the main scanning direction and the housing 6 over the main scanning direction, and light shielding at both ends of the lens body 5 in the main scanning direction. The lens holder 8 and the lens holder 9 are provided, and light in the height direction irradiated from the document M side to the sensor unit 4 side is not allowed to pass from other than the lens body 5.

  The housing 6 is made of sheet metal, and has a bottom 6f and a pair of side walls in the main scanning direction extending in the main scanning direction and bent up by 90 degrees inwardly at the end of the bottom 6f in the sub scanning direction. It has a box shape having 6 g and a pair of sub-scanning direction side wall portions 6 h extending in the sub-scanning direction and bent up by 90 degrees inward at the end portion in the main scanning direction at the bottom.

  The housing 6 has a slit portion 6e extending in the main scanning direction at the center in the sub-scanning direction. A pair of lens bodies inclined at a predetermined angle (an angle of 45 degrees or more and less than 90 degrees from the bottom of the housing 6) from both ends of the slit part 6e in the sub-scanning direction and bent inward to extend in the main scanning direction A lens body fixing portion 6a and a lens body fixing portion 6b, which are fixing portions, are formed.

  The lens body 5 is configured by a lens array such as a rod lens array or a microlens array that converges light on the light receiving body 10 on the sensor unit 4. In the first embodiment of the present invention, the lens body 5 is described as an erecting equal-magnification lens, but lenses other than erecting equal-magnification may be used in accordance with the specifications of the image sensor 100.

  The light unit 3 is formed of, for example, a transparent resin, and a light guide 11 that irradiates the reading surface of the document M while propagating light in the main scanning direction, and a light guide provided in parallel with the light guide 11. A light guide 12 having the same structure and function as the body 11, a light guide 11 and a light guide holder 13 for holding the light guide 12 at the ends of the light guide 12 in the main scanning direction, and A light source 15 and a light source 16 are provided so as to face the light guide holder 14, the end faces of the light guide 11 and the light guide 12 in the main scanning direction, and allow light to enter the light guide 11 and the light guide 12. The light source 17, the light source 18, the light source substrate 19 on which the light source 15 and the light source 16 are mounted, the light source substrate 20 on which the light source 17 and the light source 18 are mounted, and the light source 15 and the light source 16 mounting surface of the light source substrate 19. Heat transfer that improves the thermal conductivity of the light source substrate 19 by being in close contact with the opposite surface. 21, the mounting surface of the light source 17 and the light source 18 of the light source substrate 20 in close contact on the opposite side, a heat conductor 22 to improve the thermal conductivity of the light source substrate 20. The light unit 3 is fixed to the lens unit 2.

  The light guide body 11 and the light guide body 12 are formed of a transparent resin, extend in parallel with each other in the main scanning direction, and are disposed symmetrically with respect to the lens body 5. The light guide 11 and the light guide 12 do not have to be parallel over the entire length in the main scanning direction. In the embodiment of the present invention, since the light guide is exposed, it is preferable to use PMMA (polymethyl methacrylate resin) having excellent oil resistance as the light guide 11 and the light guide 12. A cycloolefin resin or polycarbonate may be used instead of PMMA.

  As shown in FIGS. 1 to 3, the light guide holder 13 has an opening 13a and an opening 13b, and the light guide holder 14 has an opening 14a and an opening 14b. The opening 13a is a through hole penetrating from the end face side of the light guide 11 to the light source 15 side. Similarly, the opening 13b is a through hole penetrating from the end face side of the light guide 12 to the light source 16 side. Similarly, the opening 14a is a through hole penetrating from the end face side of the light guide 11 to the light source 17 side. Further, the opening 14b is a through hole penetrating from the end face side of the light guide 12 to the light source 18 side.

  The light guide 11 is held by the light guide holder 13 and the light guide holder 14 by inserting the ends of the light guide 11 in the main scanning direction into the openings 13a and 14a. Similarly, the light guide 12 is held by the light guide holder 13 and the light guide holder 14 by inserting the ends of the light guide 12 in the main scanning direction into the openings 13b and 14b.

  The opening 13a, the opening 13b, the opening 14a, and the opening 14b are opposed to the end face in the main scanning direction of the light guide 11 and the light guide 12 in contact with the light guide holder 13 and the light guide holder 14, and the end faces thereof. What is necessary is that the surfaces of the light guide holder 13 and the light guide holder 14, that is, the surfaces of the light source 15, the light source 16, the light source 17, and the light source 18 are optically penetrated. That is, if the light emitted from the light source 15, the light source 16, the light source 17, and the light source 18 is formed of a material that enters the light guide 11 and the light guide 12, the opening 13 a and the opening The light guide holder 13, the light guide holder 14, the light guide 11, and the light guide 12 do not necessarily need to communicate spatially. Specifically, when the opening 12a, the opening 12b, the opening 13a, and the opening 13b are formed as through holes, the light guide 11 and the light guide are provided inside the light guide holder 13 and the light guide holder 14. A transmissive material that propagates light to the body 12 may be inserted. The light source 15 and the light source 17 are disposed on the two end surfaces of the light guide 11 in the main scanning direction, and the light source 16 and the light source 18 are disposed on the two end surfaces of the light guide 12 in the main scanning direction. However, a configuration may be adopted in which only one light source 15 is disposed on one end surface of the light guide 11 in the main scanning direction and only one light source 16 is disposed on one end surface of the light guide 12 in the main scanning direction. Needless to say.

  The light source 15 and the light source 17 are light source elements such as LEDs that make light incident on two opposing end faces of the light guide 11 in the main scanning direction. Similarly, the light source 16 and the light source 18 are light source elements such as LEDs that make light incident on two opposing end faces of the light guide 12 in the main scanning direction. The light source 15, the light source 16, the light source 17, and the light source 18 are configured by LEDs in which LED chips are resin-molded or bare chip LEDs.

  The photoelectric conversion output of the photoreceptor 10 preferably has a wide dynamic range. However, when the reading operation of the document M is driven at a high speed, the light source 15, the light source 16, the light source 17, and the light source 18 have a wide dynamic range. The drive current must be increased. As a result, heat generated from the light source 15, the light source 16, the light source 17, and the light source 18 is increased by the increased driving current.

  In order to obtain an effective heat dissipation structure for heat generation from the light source, it is necessary to employ a configuration using the heat transfer body 21 and the heat transfer body 22. Specifically, as shown in FIG. 1, the heat transfer body 21 is disposed in close contact with the light source substrate 19 on the surface of the light source substrate 19 opposite to the surface on which the light sources 15 and 16 are mounted. Here, the heat transfer body 21 conducts heat generated by the light source substrate 19 to the housing 6, and heat is diffused in the housing 6 made of metal and radiated to the outside.

  The heat transfer body 22 is disposed in close contact with the light source substrate 20 on the surface opposite to the surface on which the light source 17 and the light source 18 are formed. Here, the heat transfer body 22 conducts heat generated by the light source substrate 20 to the housing 6, and heat is diffused and radiated to the outside by the housing 6 made of metal. As described above, by having an effective heat dissipation structure, the drive currents of the light source 15, the light source 16, the light source 17, and the light source 18 can be increased, and the reading operation of the document M can be driven at high speed.

  The sensor unit 4 includes a light receiver 10 and a sensor substrate 23 on which the light receiver 10 is mounted. The light receiver 10 is constituted by an optical sensor IC, and extends in the main scanning direction beyond the reading length of the document M. The light receiver 10 receives the light collected by the lens body 5 and photoelectrically converts it. The sensor substrate 23 is attached to the surface of the housing 6 opposite to the surface facing the reading surface of the document M by a fixing means such as a screw. The sensor board 23 is a circuit board to which the photoreceptor 10 as a light receiving element is attached, and has a connector (not shown) that can be connected to the outside. The connector outputs an electrical signal photoelectrically converted by the photoreceptor 10 mounted on the sensor substrate 23 to the outside of the sensor substrate 23 as an image signal.

  Next, the arrangement of each component included in the lens unit 2 will be described with reference to FIGS. 1, 4, and 5. FIG. 4 is a cross-sectional view in the main scanning direction of the lens unit 2 in the image sensor 100 according to the first embodiment of the invention. 4, FIG. 4B is a cross-sectional view of the A-A ′ portion in FIG.

  As shown in FIGS. 1 and 4, first, the lens body fixing portion 6a and the lens body fixing portion 6b are brought into contact with both ends of the slit portion 6e extending in the main scanning direction of the housing 6 in the main scanning direction, The lens holder 8 and the lens holder 9 are fixed to the bottom 6f of the housing 6 using an adhesive or the like. The lens body 5 is placed on the lens holder 8 and the lens holder 9. The lens holder 8 has a lens body contact surface 8a and the lens holder 9 has a lens body contact surface 9a. When the lens body 5 is fixed to the housing 6, the lens body 5 can be temporarily placed as preparation for assembly. The lens body contact surface 8a and the lens body contact surface 9a may be arranged as a reference in the height direction of the lens body 5 according to a required resolution requirement.

  FIG. 5 is a cross-sectional view in the sub-scanning direction of the lens unit 2 in the image sensor according to Embodiment 1 of the present invention.

  In FIG. 5, the lens body 5 is fixed to the lens body fixing portion 6 a and the lens body fixing portion 6 b at the center in the sub-scanning direction of the housing 6 using a light shielding body 7. The light-shielding body 7 is a light-shielding member that shields a portion where the distance between the lens body 5 and the housing 6 in the sub-scanning direction varies in the main scanning direction. A material that maintains its shape is desirable. The light shield 7 fills the gap between the lens body 7 and the lens body fixing portion 6a and the lens body fixing portion 6b and covers the gap in the main scanning direction of the lens body fixing portion 6a and the lens body fixing portion 6b. It is applied from one end to the other end on the opposite side.

  The fixed portion end 6c and the fixed portion end 6d, which are the end portions in the sub-scanning direction of the lens body fixing portion 6a and the lens body fixing portion 6b, prevent the light shielding body 7 from protruding from the lens body upper surface 5a and the lens body lower surface 5b. In order to achieve this, it is arranged between the lens body upper surface 5a and the lens body lower surface 5b in the height direction. At this time, the fixed portion end 6c and the fixed portion end 6d are formed to have arbitrary lengths by performing a processing procedure of cutting the fixed portion end after performing the drawing processing of the sheet metal according to the required length. be able to.

  FIG. 6 is a cross-sectional view in the sub-scanning direction of the housing 6 in the image sensor according to Embodiment 1 of the present invention.

  In FIG. 6, the housing 6 includes a bottom 6f and a pair of main scanning direction side walls 6g which are erected by bending the sheet metal inward by 90 degrees at both ends in the sub-scanning direction of the bottom 6f. It has the structure provided with the housing | casing opening part 6i which opposes. The bottom 6f and the side wall 6g extend in the main scanning direction.

  As shown in FIG. 6A, the squeezing portion 61 is formed by squeezing a sheet metal that has a convex shape in the direction of the housing opening 6i at the center of the bottom portion 6f in the sub-scanning direction. Thereafter, the top portion 61a of the squeezing processing portion 61 is cut at the fixed portion end 6c and the fixed portion end 6d, whereby the lens body fixing portion 6a, the lens body fixing portion 6b, and the slit portion 6e are constructed. The lens body fixing portion 6a and the lens body fixing portion 6b extend in the main scanning direction. The length of the lens body fixing portion 6a, the lens body fixing portion 6b, and the slit portion 6e in the main scanning direction is shorter than the length of the bottom portion 6f in the main scanning direction.

  In FIG. 6, the lens body fixing portion 6 a and the lens body fixing portion 6 b are formed so that the thickness of the sheet metal is thinner than other portions of the housing 6 by drawing out the metal plate. The lens body fixing portion 6a and the lens body fixing portion 6b can be formed to have arbitrary lengths by cutting the fixing portion end 6c and the fixing portion end 6d after the sheet metal is drawn out. In order to perform the drawing process, it is desirable to use a rolled mild steel plate as the material of the casing 6, but aluminum or stainless steel may be used as necessary.

  In FIG. 5, the lens body fixing portion 6a and the lens body fixing portion 6b have an inclined structure that inclines from parallel to the lens body 5 side with respect to the lens body 5 and the height direction in the sub-scanning direction. That is, in the slit portion 6e, the distance in the sub-scanning direction between the lens body fixing portion 6a and the lens body fixing portion 6b is increased in the height direction toward the document M side, that is, from the bottom portion 6f toward the housing opening 6i. In other words, as it goes from the bottom 6f toward the fixed portion end 6c and the fixed portion end 6d, a structure is formed that becomes narrower and stands. The distance between the fixed portion end 6c and the fixed portion end 6d in the sub-scanning direction is slightly wider than the length of the lens body 5 in the sub-scanning direction.

  By tilting the lens body fixing portion 6a and the lens body fixing portion 6b to the lens body 5 side, when the light shielding body 7 is applied to the lens body 5 from the document M side, the light shielding body 7 is in an uncured and liquid state. In addition, the lens body 5 can be fixed to the lens body fixing portion 6a and the lens body fixing portion 6b without the light shielding body 7 adhering to the lens lower surface 5b side due to surface tension. Considering the surface tension of the light shielding body 7 and the downsizing of the housing 6 in the sub-scanning direction, the bending angle from the bottom portion 6f of the lens body fixing portion 6a and the lens body fixing portion 6b may be 45 degrees or more and less than 90 degrees. desirable.

  Positioning of the lens body 5 in the height direction and the sub-scanning direction is performed using a jig or the like. When the lens body 5 is fixed to the lens body fixing portion 6a and the lens body fixing portion 6b, the light shielding body 7 is not necessarily applied once in the main scanning direction, and the lens body 5 is fixed to the lens body fixing portion 6a and the lens body fixing portion 6b. It is not necessary to fix it to the surface, and it may be applied in several times as necessary.

  Next, a light propagation form in the image sensor 100 will be described. In FIG. 5, a solid line arrow indicates an optical path. In FIG. 5, light incident on the light guide 11 from the light source 15 provided to face one end surface of the light guide 11 in the main scanning direction is guided inside the light guide 11. The reflection on the wall surface 11 is repeated and the inside of the light guide 11 proceeds in the main scanning direction. In addition, the light incident on the light guide 11 from the light source 17 provided opposite to the other end face of the light guide 11 in the main scanning direction is opposite to the light incident on the light guide 11 from the light source 15. The light is guided inside the light guide 11 and repeatedly reflected on the wall surface of the light guide 11 to advance inside the light guide 11 in the main scanning direction. It is possible to irradiate uniform light over the entire length in the longitudinal direction (the entire length in the main scanning direction) of the light guide 11 by making the light traveling in opposite directions from both ends of the light guide 11 in the main scanning direction. It is. And the light which guides the inside of the light guide 11 by the white printed pattern or uneven | corrugated shaped scattering area | region 11a formed along the longitudinal direction (main scanning direction) of the light guide 11 is scattered, and a light guide The line light is emitted from the portion facing the scattering region 11a to the document M in contact with the transparent plate 1 as indicated by the arrow in FIG.

  Similarly, in FIG. 5, light incident on the light guide 12 from the light source 16 provided on one end surface of the light guide 12 in the main scanning direction is guided inside the light guide 12, and the light guide The reflection on the wall surface 12 is repeated and the inside of the light guide 12 proceeds in the main scanning direction. In addition, the light incident on the light guide 12 from the light source 18 provided opposite to the other end surface of the light guide 12 in the main scanning direction is opposite to the light incident on the light guide 12 from the light source 16. Then, the light is guided inside the light guide 12 and is repeatedly reflected on the wall surface of the light guide 12 to advance in the main scanning direction in the light guide 12. It is possible to irradiate uniform light over the entire length in the longitudinal direction (the entire length in the main scanning direction) of the light guide 12 by making the light traveling in opposite directions from both ends of the light guide 12 in the main scanning direction. It is. And the light which guides the inside of the light guide 12 by the white printed pattern or uneven | corrugated shaped scattering area | region 12a formed along the longitudinal direction (main scanning direction) of the light guide 12 is scattered, and a light guide Line light is emitted from the portion facing the 12 scattering regions 12a to the document M in contact with the transparent plate 1 as indicated by the arrow in FIG.

  The lens body 5 condenses the light diffused and reflected from the light guide 11 and the light guide 12 on the reading surface of the document M as line light. The light receiver 10 receives the light collected by the lens body 5 by the light receiving surface 10a and performs photoelectric conversion.

  Therefore, by using the light blocking body 7, the light receiving body 10 receives only the light that has passed through the lens body 5. That is, the direct light from the side surface of the lens body 5 can be more reliably shielded from the conventional high-precision metal casting or resin molding case, and in addition, the light receiver from the side surface of the lens body 5 The image sensor having high performance and dust resistance can be realized even in a housing formed only by processing a sheet metal capable of reducing the cost.

1 Transparent plate,
2 Lens unit,
3 Light unit,
4 Sensor unit,
5 Lens body,
5a Lens body upper surface,
5b The lower surface of the lens body,
6 housing,
6a, 6b lens body fixing part,
6c, 6d fixed part end,
6e slit,
6f bottom,
6g side wall in the main scanning direction,
6h Side wall in the sub-scanning direction,
6i housing opening,
7 Shading body,
8, 9 Lens holder,
8a, 9a Lens body contact surface,
10 photoreceptor,
10a light receiving surface,
11, 12 Light guide,
11a, 12a scattering region,
13, 14 Light guide holder,
13a, 13b, 14a, 14b opening,
15, 16, 17, 18 Light source,
19, 20 light source substrate,
21, 22 Heat transfer body,
23 sensor board,
61 Squeezing part,
61a top,
100 image sensor,
M Manuscript.

Claims (5)

A light guide that extends in the main scanning direction and emits light to the reading object;
A lens body for converging the reflected light reflected by the reading object;
A light receiver for receiving the reflected light converged by the lens body;
A housing formed by folding or sheet metal housing or holding the light guide body, the lens body, and the light receiver;
With
The housing extends in a main scanning direction, and is inclined at a predetermined angle from a bottom portion on which a slit portion through which the reflected light that has passed through the lens body passes, and both ends of the slit portion in the sub scanning direction. A pair of lens body fixing portions bent inward and extending in the main scanning direction,
An image sensor in which a side surface of the lens body inserted between a pair of lens body fixing portions and the lens body fixing portion are fixed by a light shielding body. The housing includes side wall portions bent inward from both ends of the bottom portion,
The side wall portion includes a first side wall bent inward from the bottom with respect to the sub-scanning direction, and a second side wall bent inward from the bottom with respect to the main scanning direction. Item 12. The image sensor according to Item 1. 3. The image sensor according to claim 1, wherein the pair of lens body fixing portions is formed by squeezing a center portion of the bottom portion in the sub-scanning direction into a convex shape. A pair of said lens body fixing | fixed part is that the space | interval of those sub-scanning directions becomes narrow as it goes to the edge part of the direction orthogonal to the main scanning direction and the sub-scanning direction of the said lens body fixing | fixed part from the said bottom part. The image sensor according to any one of 1 to 3. 2. A lens holder that is fixed to the bottom portion in contact with the lens body fixing portion at both ends in the main scanning direction of the pair of lens body fixing portions, and that mounts and fixes the lens body. 5. The image sensor according to any one of 4 above.

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